InnerFidelity August Update

Man! Time flies! This month some good things to report on: measurements; that Facebook thingy; and chirps on Twitter.

Measurements Added I've added some new measurements to the complete measurement pdf booklet and as individual .pdf sheets on the measurement download page:

  • Many have asked, so I finally did it: Sennheiser HD 650 measurements are up!
  • I measured the Audeze LCD-2 Rev. 2 headphone that HeadRoom just received. Audeze told me my second one was an LCD-2 Rev. 1. They measure very close to the same. I have a hard time believing my pair are Rev. 1. We'll see, I'll keep checking into this.
  • Just got my hands on the B&W C5 in-ear. Measurements, and my ears, register lots of bass.
  • The KRK sealed headphones are contenders, but a bit uneven. Measured both KNS 8400 and 6400.
  • Got some Reid and Heath Acoustics fashion cans in, the SA-850 and MA-350 do an admirable job at their price.
  • Two Beyer cans to add this month: The DT770 600 Ohm, and an early T 70 p, serial number 2!
  • Two sub-$50 headphones from Superlux, the HD 681 and HD 668B were a bit harsh, but very good at that price.
  • A big handful of modified cans were measured with two AKG K340 from Morphsci, and three DIY Fostex Orthos from scompton.
  • Also measured were the: Ultrasone Edition 8; Audeo Perfect Fit in-ear; Sony MDR-EX600 in-ear; and the Howard Light Sync ear protectors.
Facebook and Twitter
I really don't want to become just another interweb noise maker, but I also know that folks have a variety of methods they like to use to keep tabs on their interests. So, I've started both an InnerFidelity Facebook page, and an InnerFidelity Twitter feed. I will post there when a new article goes up, but I also post some smaller observations there that don't make the InnerFidelity pages.

Hope you get to listen to some good music in August. May I suggest The Klezmatics.

inarc's picture

Thank you.

khaos's picture

I have been meaning to ask the following questions:

- What is the THD+N measure? Are you doing a THD+N vs frequency (because that's the first thing every one thinks of when the see the graphs, BUT there would be of artifacts at 20, 200, 2,000 Hz)? Are you making 3 separate THD at 20, 200, 2,000 Hz and compositing the graph? Or are you injecting a signal with all three 20, 200, 2.000 Hz sinusoids and see how the system responds, IMD included?

- Does the "squareness" of the 30 Hz response simply indicate the headphones' capacity to produce a 30 Hz without attenuation? For example, the harmonic decomposition of a square wave is f + 3f/3 +5f/5... If the headphones show a -6 dB response at 30 Hz, it's enough to divide the fundamental harmonic's amplitude by 4 (?) and totally mess up the square wave response.

- Square wave responses, are they directly from the raw measure or are they HRTF compensated? A non flat response curve is enough to explain the shape of the square wave. The non flatness of the response around 2000Hz could just be the reason of the pseudo oscillations in the 300 Hz square wave response.

- Impulse response, does the amplitude of the response indicate something? Otherwise, like the square wave response, the shape is somewhat conditioned by the frequency response.

So I guess the latter questions could be interpreted as, do "response to X" graphs tell us something else than the FR response graph? My gut instinct (which means that I'm too lazy to open a signal treatment book) tells that if we just had the FR + (acoustical) phase response of a system, nothing else would be needed, square, step, impulse response could be deduced from the first graph. And I also suspect that phase response should be very good for open headphone where there would be no reflected waves.

Currawong's picture

I don't think using Twitter is making noise. What I appreciate about it is that both my friends as well as people from companies I buy things from or the sites I read are there and we can all freely converse with each other. At least for me, it's more like a huge community. Facebook though...not so much for me anyway.